Legacy Checks (deprecated)

August 02. 2015

Please note, legacy_checks are deprecated. Use custom_checks instead, an
example can be found on the Microcore migration page.

Classical Nagios checks versus Check_MK's checks

Check_MK can do many things for you and ships lots of checks based on its
special agents and on SNMP. It also allows normal Nagios plugins to
be called via MRPE. However, there are some cases, where it is preferrable
to use classical active Nagios checks configured in Nagios with define service....
Examples are:

Plugins that must be run on the Nagios server but should not be assinged to localhost.

Plugins that can be run on the Nagios server and might have a large execution time.

Checks which neither need an agent nor SNMP - e.g. check_http.

While it is - of course - possible to define those checks completely outside
the scope of Check_MK in your Nagios configuration, you can let Check_MK
do that for you. It does not perform those checks but it can create the
Nagios configuration needed for that and handles those services much like
its own checks.

Defining legacy checks in Check_MK

Defining checks to be executed in Nagios requires two steps:

Defining commands: i.e. command lines or check plugins

Defining services: on which host which command shall be executed with which parameters.

The first step can be done in main.mk by making use of extra_nagios_conf, e.g.: